Comparison of cell culture, mouse inoculation, and PCR for detection of Toxoplasma gondii: effects of storage conditions on sensitivity

The sensitivity of detection of a wild-type strain of Toxoplasma gondii by cell culture, mouse inoculation, and PCR was determined following sample storage under conditions to which clinical specimens may be subjected during transport to the testing laboratory. Sample storage at -20 degrees C significantly decreased the sensitivity of mouse inoculation. The sensitivity of cell culture decreased with sample storage at 4 and -20 degrees C. The sensitivity of PCR was reduced by storage at 4 degrees C for 48 h, freezing, and heating. These findings have implications for the selection of appropriate methods for the direct detection of T. gondii organisms in suboptimally transported clinical samples.